Low birthweight is a problem of major public health significance, since it is a major determinant of infant mortality (1-6), and a contributor to infant morbidity (1,7-14). Of particular concern is that black women have a significantly greater risk than white women of having a LBW child (Table 1), and this disparity is clearly linked to differentials in infant mortality between blacks and whites. Many etiologic factors that increase a woman's risk of having a LBW infant have been identified (see Table 2). Pregnant black women are more likely than their white counterparts to experience risk factors such as proverty, young age, and inadequate prenatal care. However, even within homogeneous categories of risk (e.g. within levels of education), black women are at greater risk of having a LBW infant. A presumptive risk factor may be increased exposure to psychosocial stressors by blacks. Prior research has suggested that exposure to stressors is associated with adverse pregnancy outcomes in general. However, prior research has been hindered by several problems. First, most studies have considered all adverse pregnancy outcomes as a single outcome variable, rather than considering LBW as a separate entity. Second, most prior research has measured exposure to stressors using the acute life events approach. This method of conceptualizing and measuring exposure to stressors is of questionable reliability and validity, in particular among blacks. Also, many studies have considered exposure to stressors without including mediating factors such as social supports in the research. Finally, many prior studies are retrospective in nature, and results may be biased due to problems with recall. Clearly, there are several crucial research needs, which the proposed project will address. These are: (1) to develop a valid and reliable tool to assess exposure to stressors and access to social supports among pregnant women; (2) to conduct a prospective study of the relationship between race, psychosocial factors and LBW, taking into account potentially confounding variables; (3) to focus specifically on LBW as a pregnancy outcome.